1. Field
The described technology relates generally to a rechargeable battery.
2. Description of Related Art
A rechargeable battery can be repeatedly charged and discharged, unlike a primary battery that cannot be recharged. A low capacity rechargeable battery is used as a power source for a small portable electronic device, such as a mobile phone, a laptop computer, and a camcorder, and a large capacity rechargeable battery is widely used as a power source for driving a motor, such as for a hybrid vehicle.
Currently, a high power rechargeable battery using a high energy density non-aqueous electrolyte has been developed, and such a high power rechargeable battery is formed with a large capacity by coupling a plurality of rechargeable batteries in series in order to drive a motor of an appliance that needs a large amount of electric power, for example, an electric vehicle.
Further, a large capacity rechargeable battery is generally formed with a plurality of rechargeable batteries that are coupled in series, and the rechargeable battery can be formed in a cylindrical shape or a square shape.
The square rechargeable battery includes an electrode assembly in which a positive electrode and a negative electrode are positioned with a separator located therebetween, a case having a space that houses the electrode assembly, a cap plate that closes and seals the case and in which a terminal hole for inserting a terminal is formed, wherein the terminal is electrically connected to the electrode assembly and is inserted into the terminal hole to protrude to the outside of the case.
If excessive heat is present or if an electrolyte solution is decomposed within a rechargeable battery, internal pressure thereof rises, so a vent fracturable at a predetermined pressure is installed in order to prevent explosion of the battery. In order to stably discharge gas through the vent, sufficient space should be formed between the vent and the electrode assembly. However, when gas is discharged, due to a discharge pressure of the gas, the electrode assembly may rise together with the gas, thereby blocking the vent hole. When the gas is not discharged due to the electrode assembly blocking the vent hole, the internal pressure of the rechargeable battery increases and thus the rechargeable battery may explode.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the described technology and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.